AMPHIPHILIC BLOCK COPOLYMERS OF VINYL ETHERS BY LIVING CATIONIC POLYMERIZATION .2. SYNTHESIS AND SURFACE-ACTIVITY OF MACROMOLECULAR AMPHIPHILES WITH PENDANT AMINO-GROUPS

Amphiphilic block polymers of vinyl ethers (VEs). \documentclass{article}\pagestyle{empty}\begin{document}$\rlap{--} [{\rm CH}_{\rm 2} {\rm CH}\left( {{\rm OCH}_{\rm 2} {\rm CH}_{\rm 2} {\rm NH}_{\rm 2} } \right)\rlap{--} ]_m \rlap{--} [{\rm CH}_{\rm 2} {\rm CH}\left( {{\rm OR}} \right)\rlap{--} ]_n \left( {{\rm R: }n{\rm - C}_{{\rm 16}} {\rm H}_{{\rm 33}} ,{\rm }n{\rm - C}_{\rm 4} {\rm H}_{\rm 9} ;m \simeq 40,{\rm n} = 1 - 10} \right)$\end{document} were prepared, each of which consists of a hydrophilic segment with pendant primary amino groups and a hydrophobic poly(alkyl VE) segment. Their precursors were obtained by the HI/I2‐initiated sequential living cationic polymerization of an alkyl VE and a VE with a phthalimide pendant (CH2 = CHOCH2CH2Im; Im; phthalimide group), where the segment molecular weights and compositions (m/n ratio) could be controlled by regulating the feed ratio of two monomers and the concentration of hydrogen iodide. Hydrazinolysis of the imide functions gave the target polymers which were readily soluble in water under neutral conditions at room temperature. These amphiphilic block polymers lowered the surface tension of their aqueous solutions (0.1 wt%, 25°C) to a minimum ≃ 30 dyn/cm when the hydrophobic pendant R was n‐C4H9 (n = 4–9). The polymers with n‐C4H9 pendants in the hydrophobic segment exhibited a higher surface activity than those with n‐C16 H33 pendants. The surface activity of the polymers also depended on the pH of the polymer solutions; the surface activity increased in more basic solutions where the ionization of the amino group (NH2)2NH3⊕) is suppressed. Copyright © 1990 John Wiley & Sons, Inc.